DESCRIPTION: This grant application responds to PA-01-032 "Career Development Grants in Occupational Safety and Health Research". It also responds to NORA's Priority Research Areas: Infectious Diseases, Indoor Environment, and Exposure Assessment Methods. Exposure to airborne biological agents, especially to pathogenic or allergenic microorganisms, may cause a wide range of respiratory and other health disorders in occupational and general populations. Also, there is a threat that certain biological agents, such as anthrax causing Bacillus anthracis spores, may be used as biowarfare agents. Exposure to airborne microorganisms is often assessed by using air samplers designed for monitoring viable microbial aerosols. Currently, there is an increased use of portable samplers for viable aerosols. In this research we will evaluate the physical and biological performances of seven portable bioaerosol samplers that have recently been introduced into the market or modified to meet today's requirements. The physical collection efficiency of the test samplers determined in a laboratory setting with different biological and non-biological test particles will be compared against conventions for inhalable particles. The biological performance of the portable samplers will be compared against an Andersen impactor and an inhalation-based sampler adapted for viable bioaerosols. The biological performance of the portable samplers will be investigated using three species of bacteria and three species of fungi. The test organisms include a simulant of Bacillus anthracis, which will allow determining the efficiency of the samplers when collecting airborne B. anthracis spores. The efficiency of portable samplers when collecting airborne bacteria and fungi will also be evaluated in indoor and outdoor field environments during different seasons. Based on the obtained results, the researchers will develop practical recommendations for using the tested portable bioaerosol samplers, especially as it relates to exposure assessment and particle penetration into the respiratory system. The recommendations produced by this research can then be used by the health professionals and other stakeholders performing bioaerosol exposure monitoring. Future directions of this research will be development of a portable bioaerosol sampler, sampling characteristics of which follow conventions for inhalable, thoracic and respirable particles. [unreadable] [unreadable]